stefanie stahl shows us it could safe women's lives. >> good job! >> reporter: mcbain is rewarded when he shows he has found a certain scent. >> yes, good boy! >> reporter: this is a rare look inside the renowned pennvet working dog center on the first day of a new study that could change the future of cancer detection. >> i know our dogs are lifesavers. >> reporter: previous studies have shown dogs can detect certain medical conditions like a seizure before it happens. now this select group of canines is being trained to detect ovarian cancer. marta dexler donated tissue for the project. she has advanced ovarian cancer. >> i feel very large gratitude that i can be a little tiny part of it. >> reporter: ovarian cancer is a silent killer because there are often no symptoms and no effective screening. so it's usually found late after it's spread. well, the dog could change that. >> if this works in a couple of years two or three years, all women could have the chance to have this early diagnostic tool. >> reporter: cynthia otto the director here says